Sentence examples for this is an illusion from inspiring English sources

This is an illusion".

Yet this is an illusion.

But ophthalmologists say this is an illusion.

Strictly speaking, this is an illusion.

"But I think this is an illusion".

"This is an illusion and misinformation.

This was an illusion.

This was an illusion, of course.

I have no doubt — can this be an illusion?

I suppose it would be fair to say that all of this was an illusion.

But you only had to look around to realise that this was an illusion.